3D printing builds a nanowall

3D printing went nano again last week as researchers in Korea published a paper which shows that nanoscale 3D objects – like free-standing nanowalls – can be constructed using 3D printing technology.

3D printing has been a go-to tool in making large things for decades. As 3D printing technology advances, new applications become possible in making very little things as well. 3D printing already has an important presence in nano-scale realms. It's an essential instrument in the extreme miniaturization of components in integrated circuits, in biofabrication and in tissue engineering, as well as in some drug manufacturing applications where 3D printing can offer greater control at the molecular level.

3D printing in nanofabrication could make processes cheaper, faster, and reduce waste. Armed with pre-patterned substrates and 3D printing technology, researchers may be able to realize new complexity in nanoscale 3D fabrication. The most recent development in 3D printing on the nano-scale comes from a team led by Ho-Young Kim, a professor at Seoul National University in South Korea.

Schematic of the experimental apparatus. (Image credit: American Chemical Society)

Electrospinning is a technique which uses an electrical charge to draw a micro or nano-scale fibers from a liquid. It's a relatively cheap and easy way to produce polymer nanojets which may be used to create nanoscale fibers. According to professor Kim, nano-scale fiber streams are often so chaotic that it is difficult – if not impossible – to control individual fibers. In their recent work such nano-scale fiber streams are kept in relative order using a thin metal electrode line.

Nanowall built on a stationary metal line. Top: Illustration of the deposition of a nanofiber to yield a free-standing nanowall. Bottom left: SEM (scanning electron microscopy) images of the free-standing nanowall. Bottom right: SEM image of the end of the nanowall that resembles a racket. (Image credit: American Chemical Society)

Using this line, the polymer nanojet may be stacked to form a wall-like structure. The team showed that tension in the polymer fiber may be balanced using the electrostatic interaction of the fiber and a metal ground, and that the length of a nanowall may be controlled translating the substrate.

The team suggests their novel 3D printing scheme may be applied in the development of nanoscale objects like bioscaffolds, nanofilters, nanorobots, and nanoelectrodes.